Various hitches and hitch connectors have been previously devised for attaching a trailer to a tow vehicle, such as a receiver type hitch, a 5th wheel hitch, and a gooseneck hitch. Receiver type hitches are positioned at the rear of the tow vehicle and typically attach to either the vehicle's bumper or frame. A hitch attached to the vehicle's frame generally has a higher load carrying capacity than a hitch attached to the tow vehicle's bumper. Receiver type hitches include a mechanism for releasably attaching a ball connector to the hitch. This enables differently sized ball connectors to be used interchangeably with the same hitch. The trailer includes an appropriately configured coupler sized to match the size of the ball connector attached to the hitch. The trailer can be releasably attached to the tow vehicle by properly engaging the coupler with the ball connector connected to the hitch.
For towing large heavy trailers a different hitching mechanism may be needed for stable and safe towing. A wide variety of different hitching mechanism for towing heavy loads have been devised. Two such hitches are commonly known as a gooseneck hitch and a 5th wheel hitch. They are typically used for towing relatively large trailers, such as a recreational trailer, horse trailer, utility trailer, and the like. A typical 5th wheel setup a pin box suitably attached to an underside surface of the trailer. Attached to pin box is a hitch connector commonly known a king pin connector. The pin box is generally cantilevered from a front end of the trailer. This is done to provide sufficient clearance between the tow vehicle and the trailer, particularly when negotiating turns.
A wide variety of vehicle types may be used as the tow vehicle, including a conventional pick-up truck, flatbed truck, tractor truck, or the like. In the case of a pickup truck, the hitch is generally attached to a bed of the vehicle. It is generally desirable to position the hitch either over or slightly forward of a rear axle of the tow vehicle. This provides for more stable towing of the trailer than if the hitch were positioned behind the rear axle.
A gooseneck hitch setup is similar in some respects to a 5th wheel. The gooseneck hitch is generally positioned on the tow vehicle at substantially the same location as a 5th wheel hitch. The gooseneck hitch itself, however, differs significantly from a 5th wheel hitch. A gooseneck hitch typically consists of a ball hitch suitably attached to the tow vehicle. In the case of a pickup truck, the ball hitch is generally attached to the floor of the bed. The gooseneck ball hitch is typically positioned lower on the tow vehicle than a 5th wheel hitch. The gooseneck connector attached to the pin box on the trailer includes a suitably configured connector affixed to the end of the gooseneck. The gooseneck connector can be releasably engaged with the ball hitch on the tow vehicle.
Generally speaking, a trailer having a king pin connector can only be connected to a tow vehicle having a 5th wheel hitch, and trailers incorporating a gooseneck hitch can only be connected to a tow vehicle that has an appropriately configured ball hitch. This limitation often creates problems in situations where it is desirable to use the same vehicle to tow multiple trailers incorporating different hitch arrangements. For example, if the tow vehicle has a 5th wheel hitch and the trailer to be towed has a gooseneck connector, the user would be required to proceed with the time consuming task of removing and replacing the 5th wheel hitch with a gooseneck ball hitch. Not only is this process time consuming, but it also results in the added expense of having two different types of hitches on hand.
In an attempt to overcome some of the problems associated with having multiple trailers utilizing different hitching devices, various adapters have been-previously devised. The majority of the adapters convert a king pin connector to a gooseneck connector. The adapter is typically configured to attach directly to the trailer's existing pin box. Such an arrangement may, however, compromise the structural integrity of the pin box since the pin box may not have been designed to carry the additional mechanical load that may result from using the gooseneck adapter. The additional load is due in large part to the increased torsional moment applied to the pin box as a result of increasing the distance between the pin box and the hitch connector. Because of these and other limitations of existing hitch mechanisms, it is desirable to develop a pin box assembly that will allow various types of hitch connectors, such as a gooseneck connector and a king pin connector, to be used interchangeably with the same pin box.